Paper packaging material and method of making the same



Feb. 25, 1941. s MUSHER 2,233,142

PAPER PACKAGING MATERIAL AND METHOD OF MAKING THE SAME Filed May 29,1959 ANTI-OX \DANT SUCH AS HYDROQUINONE CELU LOS\C PACKAGING MATERIALsucH As PlNE BOARD [3 HEAT\NG OVEN igUSPEgiFlgN ORNSOLUTION D F A x A TINVENTOR Sidney Mil/Sher BY A TORNEY Patented Feb. 25, 1941 I PATENTOFFICE A PAPER. PACKAGING MATERIAL AND METHOD or MAKING 'rnn slum SidneyMasher, New York, N. Y., assignor 'to Masher Foundation Incorporated,New York, N. Y., a corporation of New York Application May 29. 1939,Serial No. 216,413

9 Claims.

This invention relates to an improved paper sheet wrapping material,capable of prolonging the life of packaged organic compositions andparticularly when such compositions contain I i 5 glyceride oils andfats,

' juice, butter, candies and confections, ice cream, cheese, bacon,hams, beef, oranges, lemons and other citrus fruit, corn flakes, wheatcakes, shredded wheat, nuts. potato chips, etc., all of which aresubject to oxidative deterioration and 20 development of objectionableoil-odors and fiavors during normal storage or distribution.

In addition, the entrained air in the package readily accelerates thisdeterioration for it is not practicable, where celluloslc packagingmaterials are used, for the packaged product to be held under vacuum orunder inert gases such as nitrogen, carbon dioxide, etc.

An object of this invention is, therefore, the production of improvedpaper packaging materials which will prolong the life of packaged organic compositions and which will be readily acceptable for use inconjunction with food compositions and without objection by health andgovernmental agencies.

Still further objects-and advantages will appear from the more detaileddescription set forth below, it being understood, however, that thismore detailed description is given by way of illustration andexplanation only, and not by way of limitation, since various changestherein may be made by those skilled in the art without departing fromthe scope and. spirit of the present invention,

In accordance with this invention, it has surprisingly been found thatcertain materials applied to paper wrappers will substantially balancethe effect of the air and the naturally oxidizable characteristics ofthe packaged organic compocookies, cakes and cookery products, milk,orange being incontact with air. For example, less than 10% of the totalsurface area ofthe packaged composition may be in contact with the sheetpackaging material and 90% or more in contact with air, butstabilization against oxidative deterioration is nevertheless obtained.

In accomplishing the results of this invention, there are preferablyapplied certain di-substituted benzenes to the paper packaging material,the substances most satisfactorily employed being the hydroxy(ii-substituted benzenes, preferably in para position, and lesspreferably the hydroxy di-substituted naphthalenes. As a general rule,these substances should contain not more than '14 carbon atoms andpreferably not over 10 carbon atoms. Apparently these compounds formsome combination with the cellulose oi the paper packaging materials,such combination being of a physical or chemical nature, with the resultthat the combination of the paper material and the aromatic compound hasbeen activated to develop aid most satisfactorily in obtaining thedesiredresults, such sizing materials including glycerine and itsrelated sizing compounds, carbohydrates such as starch and sugars,dextrin and carbohydrate gums such as gum arabic; karaya, traga canth,etc.

Less preferably there may be utilized as the sizing carrier the highmolecular weight proteins and protein containing materials such ascasein, soya proteins, partly or wholly coagulated gelatin or glue, etc.

The stabilizing aromatic compounds are preferably applied in amountsranging from 0.001% to 1% against the'weight of the paper sheetpackaging material. Generally, about 0.05% to 0.25% by weight is thedesired amount to give satisfactory protection. a x

The preferred aromatic hydroxy compound to use in accordance with thisinvention is hydroquinone. Other useful di and. tri-hydroxy compounds,the hydroxy groups of which may have been etherized, include guaiacol,phloroglucinol, resorcinol, pyrogallol, tyrosine, eugenol, thymol,vanillin, gallic acid and gallotannin.

The hydroquinone should be applied to the paper so that it is present atthe surface of that paper and desirably spread out in a thin film at thesurface oi the paper and on that surfacu which is to be placed intocontact with the edges of the packaged product.

As an example of the method by which the hydroquinone or similarcompound may be applied, it may be added to the tub sizing tanks throughwhich the paper or paperboard passes, using from 0.5% to 15% 0f thehydroquinone against the weight of the water and other materialscontained in the size. About 2% of hydroquinone against the weight ofthe size is a satisfactory amount. When the sheet material, whether itbe parchment paper, sulfite paper, greaseproof paper, glassine paper,prime stock or secondary stock board, passes through the sizing tankcontaining the hydroquinone, sumcient of the hydroquinone will be pickedup on the sheet to give marked stabilizing activity to packaged organiccompositions.

A particularly desirable method for the application of the hydroquinoneto the sheet is first to admix it with a carrier as indicated above. Forexample, to tapioca or corn starch may be added from 0.5% to 5% byweight of hydroquinone and thoroughly admixed therein. Where desired,the starch may then be boiled or treated with an enzyme to prepare forsizing and utilized in the sizing troughs for application to thepackaging material.

Desirably, the paper or board may be allowed to pass through the sizingtrough so that a portion of the hydroquinone adheres to the surface ofthe paper or board. In the case of parchment paper, the hydroquinone maydesirably be present in the sizing troughs through which the paperpasses after the sulfuric acid and alkali neutralization parchmentizingoperation.

By utilizing a starch as a carrier for the hydroquinone, the individualparticles of the hydroquinone are sumciently well dispersed throughoutthe tub carrying thesize so that the paper or board which passes throughit picks up a uniform quantity of the hydroquinone.

Exmrrr: I

A 30 lb. stock greaseproof paper was passed through a bath consisting of95% water and 5% hydroquinone. The paper was then dried in a vacuum ovenat 65 C., it being estimated that 0.1% of hydroquinone against theweight of the paper was applied. The paper thus made was used for thepackaging of soda crackers, only the edges of which were in contact withthe paper and about 98% of the surface of the crackers being exposed toair. The crackers thus packaged were compared in keeping quality withcrackers packaged in ordinary untreated greaseproof paper by holding inthe dark at 98 F. and observing for rancidity.

' Rancidity observed after Crackers in untreated paper 9 days Crackersin treated paper 16 days Exmrrz II A preboiled dried powdered cornstarch was thoroughly mixed with 5% by weight of hydroquinone. Thestarch containing the hydroquinone was sized on 'glassine paper bypassing the paper before supercalendering through a size bath containing92% water and 8% of the starch-hydroquinone combination. The paper wasthen supercalendered and dried. This treated glassine was made into bagsand used for the packaging of potato chips, only a portion of the edgesof a minor number of which were in actual contact with the paper. Thepotato chips weight.

was gelatinized by boiling in 7 times its weight essence thus packagedand held in the dark at 98 F. were free of objectionable rancidity forover twice as long as a similar lot of potato chips packaged in ordinaryuntreated glassine and held under similar conditions of storage.

This method of treating paper to retard oxidative deterioration ofpackaged products is in no way related to the filtering out of anyspecial light rays since the desired results are obtained even where notransmission of light is involved and the packaged composition is storedin the dark away from all light rays. Moreover, the protective materialsof the instant invention are incapable of producing any special lightfiltration benefits.

The process of the present invention is particularly concerned with thetreatment of those papers and boards which are normally opaque and arenot changed in color by this treatment.

The process of the present invention is most particularly of value inconnection with the plain (non-regenerated) types of papers and boardswhereby no hard surface film is present. Where a hard surface film ofthe nature of the regenerated cellulosic films, resinous sizingmaterials, etc., is utilized, the results of the present invention arenot readily obtained and most desirably, the treatment of the presentinvention should be given to ordinary absorbent paper and board.

Surprisingly, it has been found that the treatment of paper withhydroqulnone in the manner indicated will show even better results thanwhere the same amount of hydroquinone is added to the packagedcomposition.

EXAMPLE III Crackers A To 1000 grams of cracker dough containing 120grams of bleached lard was added 0.01 gram of hydroquinone. The crackerswere baked, packaged 3 crackers to each package with ordinary parchmentpaper and stored in the dark at 98 F. until rancidity was detected.

Crackers B 1000 grams of the same cracker dough but without thehydroquinone were used in the manufacture of crackers, the crackersbaked and packaged, using 3 crackers to each package, with parchmentpaper. In this 'case one side of the parchment paper had previously beensoaked with water containing 0.01 gram of hydroquinone until all thewater plus the hydroquinone was adsorbed on the paper, and the paper wasthen dried with the hydroquinone present on the surface of that side ofthe paper which would be adjacent to the edges of the crackers whenwrapped. These crackers were tested in the same manner as Crackers A.

In both cases only about 2% of the total surface area of the crackerswas exposed to the parchment paper, the balance being exposed to air.

Observations for rancidity were made with the following results:

Rancid after Crackers A 31 days Crackers B days EXAMPLE IV A mixture wasprepared comprising 1% of hydroquinone and 99% of tapioca starch by Thestarch-hydroquinone combination of water and then suilicient additionalwater was added so that only 6% or the gelatinized starch-hydroquinonecombination was present in the water. Board made of sulphite secondarystock was passed through this bath and the board was then heated to 220F. until thoroughly dry. The board thus made was used for the packagingof sweet wafers, only the edges of which touched the board. The wafersthus packaged were found to be extremely resistant to rancidity and tothe development of carton odorsand tastes.

The protection afforded is of particular value in view of the fact thatthe addition of hydroquinone to crackers would be prohibited because ofthe questionable edibilityof that product whereas, in accordance withthis invention, the

hydroquinone may be utilized without question by food authorities.

' Furthermore, it is not well understood as to why the presence ofhydroquinone on the paper should be so much more eilective than where itis added to and dispersed in the packaged composition. v

The present specification and claims are lim 'ited to those papers thatare sized or coated with wax, parafiin, hydrogenated fat or similarsurface coatings of non-resinous character. The hydrotion to packagedoil or fat containing organic compositions. Such papers or boards are,after the application of the, hydroquinone as a sizing, surface coatedwith paraflln or impregnated with paraflln oils and utilized in thepackaging of milk,

orange juice, meats, fish and poultry for storage, biscuits andcrackers, caramels and candies, etc.

EXAMPLE V A sulfite paper was sized with hydroquinone in the mannerdescribed in Example I. The paper was then waxed by passing through aparaflin containing trough so that the finished paper contained 30% byweight of paraflin. The paper thus made was used for the wrapping ofpork loins which were placed in the dark at 35 F. for 2 months. Eventhough the hydroquinone was covered by the paraffin film. and not. indirect contact with the loins, they were nevertheless substantiallystabilized against oxidative deterioration for at the end of the 2 monthperiod, they were in good condition and had a good flavor whereassimilar loins wrapped in waxed paper that had not been sized with thehydroquinone before wrapping had a noticeable off-flavor and wereconsiderably darker in color.

The treatment of paper packaging materials with hydroquinone before thewaxing thereof is of particular importance because there is avoided anypossibility of contact between the packaged organic composition and thehydroquinone due to the paraffin layer. Even though, therefore, thestabilizer used be objectionable if it were to contact the packagedcomposition such as if hydroquinone or pyrogallol were to be in intimatecontact with a packaged food product, and even r the dark.

though such objectionable stabilizer were not in direct contact with thepackaged food product to qualitystock such as of pine board which is soreadily susceptible to transferring objectionable cardboard'odors topackaged compositions.

Eximru: VI

A pine stock board was sized with hydroquinone by passing it through abath containing 10% of hydroquinone by weight. Part of the board thustreated was dried in a vacuum oven at F.

and part subjected to a temperature of 22031 until dried. The-boardswere then used forthe packaging of sweet cookies and held at. 98 F. inIt was observed that the cookies packed in the board which was dried at.220 F. kept free oithe objectionable cardboard" odor and flavor forabout 40% longer than the cookies packed in'the board which was dried at135 F.

It is not known as to why the heat treatment should so definitelyincrease the stabilizing value of the aromatic compositions describedfor it v contaminate it, nevertheless the hydroquinone or a wouldnormally be expected that the heat treatsome reaction. occurs throughthat bath, and then to subject the paper or board to an elevatedtemperature of at least 212 F. and preferably to 220 F. or higher.

The hydroquinone may much less desirably be added to the beaters but ithas been observed that when the addition is made to the beaters, no morethan 50% and in most cases much less effectiveness is obtained thanwhere a surface application is made. In the case of the low gradesecondary stock boards, and where the stocks in the beaters aresubjected to a temperature of about F. and preferably to 210 F. orabove,the hydroquinone may beadded to the heaters. particularly desirable inthe treatment of pine stock and other low gradeboard.

It is undesirable to mix the hydroquinone with the wax and then applythe mixture to the paper or board because of reduction in themoistureproofness and contamination of the paraffin or wax. Moreover,the results obtained are in most cases not as pronounced as when thehydroquinone is under theparailin film as described in this invention. I

The hydroquinone or similar material used in acco dance with thisinvention does not work on the principle of absorbing light raysresponsible for the oxidative deterioration of packaged madein'accordance with this invention is primarily intended for utilizationin the packaging of foodstuffs that are held on grocery store shelves orunder refrigeration'where they would 70 organic compositions and thepaper or board,

55' Thisis" not be exposed to such objectionable light rays allegedlyresponsible for racidity of fats exposed tothem.

As stated above, the preferred compounds utilized are absorbed at thesurface of the paper sheet material without causing any substantialchange in the color or appearance thereof and the stabilizing activitywhich is obtained appears to arise from catalytic chemical contactaction without any light filtration or direct combination with thepackaged composition, although there may be a combination with the paperor board or polyhydroiwlated aliphatic materials utilized as carriers togive enhanced benefit.

The preferred compounds are those which have a single aromatic ring.preferably a phenyl ring, and which are para substituted.

Where the paper is supercalendered, it is desirable'to apply thehydroquinone before the supercalendering operation.

Although it is usually desirable to utilize the hydroquinone or otheraromatic compound by itself, as a surfacing, it is also possible to usecombinations of the aromatic compounds with lecithin, kephalin,phosphoric acid, phosphatides, glucose, sucrose, lactose or othersugars, and less preferably with the alkali metal phosphates, calciumphosphates, tartaric, citric or other polybasic and/or polyhydroxyaliphatic acid, this combination being utilized particularly in thetreatment of secondary stock papers and boards such as pine stock boardand where the paper is subjected to an elevated temperature of at least212 F. and preferably to 220 F. or above after the application of thecombination thereto.

. These added compounds may generally be used in amounts ranging from 5%to 100% of the hydroquinone used.

Upon the accompanying drawing is diagrammatically shown certain aspectsof the present invention.

Figure 1 is a diagrammatic transverse sectional 4 view upon an enlargedscale showing a cross section of the paper packaginfmaterial afterpreparation according to the present invention.

Figure 2 shows said packaging material made up into a package andcarrying an organic material subject to oxidative deterioration which isonly in contact with said paper packaging material over a minorproportion of its own surface and of the surface of the packagingmaterial.

Figure 3 is a diagrammatic layout of the method of applying theantioxidant on the paper and showing also the subsequent heat treatmentto which the paper after the application of the antioxidant thereto issubjected.

Referring to Figure 1, A is the surfaced packaging material, a being thesurfacing of the antioxidant, such as hydroquinone, applied to the paperbase b with or without a subsequent heat treatment to enhance theactivity of the antioxidant as a result of the reaction between theantioxidant and the cellulosic packaging material.

In Figure 2, is shown a package made of the 5 surfaced packagingmaterial A containing the crackers which are only in contact with thepackaging material A at their edges, leaving a major portion of the areaof the crackers exposed to the air inside of the package and to any airwhich 70. may pass through the walls of the package, where such packageis unwaxed or where the wax coating has broken down.

It has been found that, although there is a substantial exposure to air,nevertheless this very slight contact with the activated antioxidantpackaging material has resulted in a communication of the antioxidantactivity apparently to the whole body of the organic material, in thiscase soda crackers, within the package.

In Figure 3, the paper material A is shown as 5 passing through thesurfacing bath over the rollers in, ii and i2, where the paper picks upthe desired amount of the antioxidant in aqueous solution or suspension.After the excess solution has been removed at l2, the paper may be sub-10 jected to the heat treatment in the oven E by being passed a largenumber of times over rollers I3.

It will be noted that the packaged organic products, which in this caseare soda crackers 15 or biscuits C, have only their edges C in contactwith the coated packaging material A but nevertheless are highlystabilized against oxidative deterioration.

The present application is a continuation in 20 part of applications,Serial No. 144,489, filed May 24, 1937 and Serial No. 190,887, filedFebruary 16, 1938'.

Having described my invention, what I claim is:

1. A process of making a flexible sheet wrap- 2 ping material comprisingfirst applying to the sheet packaging material a surfacing of anantioxidant which is spread over the entire surface thereof and thenapplying an overcoat of a water repellant coating material, saidantioxidant being 30 hydroquinone and said coating material beingparaflln.

2. A process of preparing an antioxygenic wrapping paper which comprisespassing the paper through a bath containing about 10% hydroquinone andwater to obtain complete surface coverage on said paper, drying thepaper and then applying an overcoat of a wax covering over thehydroquinone.

3. .A flexible sheet wrapping material which 40 has been surfaced withan antioxidant which is spread over the entire surface thereof, andwhich contains over said surfacing of said antioxidant a water repellantwax material which has been spread over the surface of said packagingmaterial and over the surface of said antioxidant, said antioxidantbeing hydroquinone and said wax material being parafiin.

4. A process of making a flexible sheet wrapping material whichcomprises first treating the 50 wrapping material with antioxygenicvanillin and then applying an overcoat of a wax.

5. A process of making a flexible sheet wrapping material whichcomprises first treating the wrapping material with antioxygenicgallo-tannin 55 and then applying an overcoat of a wax.

6. A flexible sheet wrapping material which has been treated with anantioxygenic compound selected from. the group consisting ofhydroquinone, guaiacol, pholoroglucinol, resorcinol, g0 pyrogallol,tyrosine, eugenol, thymol, vanillin, gallic acid and gallo-tannin,and'which contains an overcoat of a wax.

'7. A process of making a flexible sheet wrapping material whichcomprises first treating the 05 wrapping material with an antioxygeniccompound selected from the group consisting of hydroquinone, guaiacol,pholoroglucinol, resorcinol, pyrogallol, tyrosine, eugenol, thymol,vanillin, gallic acid and gallo-tannin, and then apply- 70 ing anovercoat of a wax.

8. A flexible sheet .wrapping material which has been treated with anantioxygenic compound selected from the group consisting ofhydroquinone, guaiacol, pholoroglucinol, resorcinol, 76

pyrogallol, tyrosine, eugenol, thymol, vanillln, gallic acid andgallo-tannin, and which contains an overcoat of a parzifiin.

9. A process of making a flexibl e sheet wrapping material whichcomprises first treating the wrapping material with an antioxygeniccompound selected from the group consisting of hydroquinone, guaiacol,pholorogluclnol, resorclnal, pyrogallol, tyrosine, eugenol, thymol,vanillin, gallic acid and gene-tannin, and then apply ing an overcoat ofa paraffin.

I I T SIDNEY MUSHER.

